In the world of Erdas, every child must discover if they will summon a spirit animal, a rare and incredible gift. Conor, Abeke, Meilin, and Rollan were rare even among those few. They summoned legendary animals -- brave guardians who were reborn to protect their world. Now more of these legends are appearing across Erdas, bonded to special children. But a dark force has emerged. Older than memory, it has slept for centuries beneath the surface of the world. With the power to tear away spirit animals, it begins a rampage that will be felt in every corner of Erdas. If the young heroes can't stop it, the darkness will first consume the spirit animals . . . and then the world.